In a Commercial Mobile Alert Service (CMAS) system, currently emergent alert information for public security is sent to mobile terminal users mainly by means of cell broadcast. The types of alerts include: a state-leader-level alert, a disaster alert, a terrorist attack alert, a child trafficking alert and other alerts.
At present, in a general CAMS system over the world, an alert message is sent to mobile terminal users through a particular cell broadcast channel, by which the alert message may be sent in real time and received conveniently. However, small amounts of information is included in the alert message, i.e., some simple text messages are merely included in the alert message and larger video/audio files are difficult to be delivered, so that the current alert situation cannot be perceived intuitively by the users.